Emotor and inverters etc still cool (<10 deg rise) after 10km driving around at 10-30kmph. Mains power meter on recharge works out to about 140Wh/km. (the inverters have built in 10A LA chargers ea. that work fine with 12V lithium packs and can float at 3.45Vpc) 4 IEC leads to a plug board covers the charging.

There is cell top BMS on each TS but almost not required once cells are balanced.
Inverters shut down at 10.5V

Just goes to show, V and A are only numbers if the electronics is there to push it around !

This is a long way from 50 or 100 + kW but cost may be less than the BMS etc for higher voltage packs ?

No regen is offered here, but relatively simple to add via DC-DCs back to 12V battery. (no negative torque demanded of VFD in this torque mode so there is little if any regen in this setup. Brake pedal could be used to apply -ve torque demand)

Battery / inverter setup in the boot

Screen grab of log data, values are at cursor

Anyway, just food for thought.

edit:added pics, converted some text to English

Last edited by acmotor on Wed, 06 Jun 2012, 10:13, edited 1 time in total.

So I guess the question will be is the 10% loss in the inverter worth the extra saftey of using a 12V battery pack and reduced cost on BMS and charging systems?
Also how big do you think the inverter would be for 100kVA?

Help prevent road rage - get outta my way! Blasphemy is a swear word. Magnetic North is a south Pole.

Using an ultra cap bank on the DC bus would be the way to go so the inverter is only supplying the average power and the say 100kW peak is only for seconds from the cap bank.
Most motor arrangements would at best work at peak power for 60 seconds or less anyway.

Managing the regen into the cap bank would probably make up for the inverter loss.

If an EV had a 20kWh battery pack then average power consumption would only 10 to 20kW. That's all the inverter you'd need.

Mind you, if you are prepared to use all that inverter silicon then a lower voltage emotor and VFD would be the go anyway ? Its a question of what is off the shelf at present although the old higher voltage / lower current factor for VFD and emotor is still there.

I seem to recall that idea being posed once before but with a battery pack rather than inverters.
The problem with the above sketch is that the inverter outputs are diode bridges so the regen current would just cause the inverter outputs to momentarily climb (until some high voltage limit stopped regen) and not actually charge the caps.
You would need a PWM/inductor clamping system on the inverter(s) output.
i.e. A PWM zener.

I saw this and thought, oh acmotor must of had these parts lying around and that they would be big $ for the 3000W inverters if you got them new.
But it looks like they are only $208USD.

I wonder if you could use 4 of these inverters, along with a 3-400AH 12V Lithium battery to replace the HV battery in a NHW10 Prius?

There is a company in New Zealand that sells the Power Jockey which does a similar thing by feeding around 1000W from the 12V accessory battery into the HV battery through an inverter. Props up the aging Nimh battery apparently.